A network has many resources which are vulnerable to attacks from external networks, so developers have created mechanism for protecting against such attacks. Resources may include servers, printers, network hardware and software, and others. Network Security Gateways (NSGs), which sit on the edge of protected and external networks, provide security to a protected network and generally operate in one of two modes. In “promiscuous” mode, besides sending packets between an external and protected network, the NSG monitors copies of incoming network traffic for intrusion pattern characteristics and generates alarms in response to detecting such patterns. In “inline” mode, network traffic is scanned prior to being passed to a protected network by the NSG to determine whether it contains a hostile signature. In addition to generating alarms in the inline mode, the NSG can prevent traffic from reaching the protected network. If either actuation is detected, the NSG prevents the network from receiving the traffic. Generally, NSGs operating in the inline mode have two physical ports, one coupled to the outside network and one coupled to the protected network. On the other hand, NSGs operating in promiscuous mode only need one physical port to received network traffic.